title: Influence of the insertion time and number of polyps on miss rate in colonoscopy.
abstract: OBJECTIVE
  Colorectal polyps can be missed even during a meticulous colonoscopy by an experienced colonoscopist. The aim of this study was to investigate patient-, procedure-, and polyp-related factors affecting the miss rate of polyps on colonoscopy.
  
  
  METHODS
  From March 2001 to February 2006, a total of 285 patients undergoing screening colonoscopy followed within 2 months by colonoscopy for polypectomy were enrolled. The main outcome measurements were factors associated with miss rates of polyp and the conditions for reducing missed polyps on colonoscopy.
  
  
  RESULTS
  From the 285 colonoscopy pairs, a total of 1326 polyps were found. Overall, 350 of the 1326 polyps were missed (26.4%). Among those, 59 polyps (4.4%) were only seen on the first colonoscopy and 291 polyps (21.9%) were found only at the second colonoscopy. Patient-related factors were male sex (Odds Ratio (OR) 2.11, 95% Confidence Interval (CI) 1.21-3.70) and older age (OR 2.51, 95% CI 1.48-4.30). Procedure-related factors were colonoscopy by clinical fellows (OR 2.20, 95% CI 1.02-4.84) and delayed insertion time (OR 4.10, 95% CI 2.14-7.86). Polyp-related factors were more than four numbers of polyps (OR 4.48, 95% CI 1.91-10.5). However, a large polyp was less frequently missed on colonoscopy (OR 0.10, 95% CI 0.05-0.19).
  
  
  CONCLUSIONS
  In usual clinical practice, colon polyps were frequently missed on colonoscopy. Comprehensive analysis of patient should be required to reduce the miss rates.
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jae Hak
authors.initials: JH
authors.lastname: Kim
authors.forename: Yong-Soo
authors.initials: YS
authors.lastname: Kim
authors.forename: Jae Hee
authors.initials: JH
authors.lastname: Cheon
authors.forename: Sang Kil
authors.initials: SK
authors.lastname: Lee
authors.forename: Tae Il
authors.initials: TI
authors.lastname: Kim
authors.forename: Sungmin
authors.initials: S
authors.lastname: Myoung
authors.forename: Won Ho
authors.initials: WH
authors.lastname: Kim
mesh_terms: D018256:Adenomatous Polyps / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002983:Clinical Competence; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012680:Sensitivity and Specificity; D012737:Sex Factors; D013997:Time Factors